The present invention comprises a new and distinct cultivar of Chrysanthemum botanically known as Chrysanthemum morifolium, and referred to by the cultivar name ‘Swing Time Yellow.’ ‘Swing Time Yellow,’ identified as 20230-6, originated as a naturally occurring whole plant mutation grown in a controlled planting of the variety ‘Swing Time Dark’ (U.S. Plant patent application Publication No. U.S. 2003/0009810), in Chichester, West Sussex, United Kingdom. The new variety ‘Swing Time Yellow’ has been asexually reproduced by vegetative cuttings in Chichester, West Sussex, United Kingdom and the distinguishing characteristics are retained through successive generations of asexual reproduction.